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After a brief interlude of democratization ushered in by the Arab uprisings in 2011, Egypt has taken a sharp turn towards authoritarianism. While political repression has disintegrated social movements and demobilized seasoned activists, the outbreak of the coronavirus has afforded an opening for new voices, such as those of healthcare workers who took to social media to expose mismanagement and malpractice within the healthcare sector. The article examines acts of whistleblowing performed by Egypt's healthcare workers during a public health crisis, drawing on qualitive research materials collected from social media, trade union press releases, and interviews conducted with a small group of doctors and pharmacists. The article contends that individual acts of whistleblowing can produce unconventional practices towards collective claim-making prompting multiple forms of contentious mobilization. The findings highlight main features that facilitate diffusing and sustaining mobilization under prohibitive authoritarian settings. [ABSTRACT FROM AUTHOR]

The intolerance to Acetylsalicylic Acid (ASA) can be detected by conducting oral provocation testing (OPT), which is to gradually introduce low doses of ASA. To perform this test, hospital pharmacies compound small batches of different low-dosage ASA capsules. This work aims to validate a method for fast HPLC-UV assay that allows routine quality control and physicochemical stability studies of capsules.

Sodium alginate with different molecular weights (55, 170, and 320 kg mol -1 ) were chemically modified by grafting methacrylic moieties onto the hydroxyl groups of the alginate backbone. The methacrylation was optimized to obtain different degrees of modification. Chemically cross-linked hydrogels were obtained following UV-light irradiation in the presence of a photoinitiator. The swelling behavior and the mechanical properties were observed to depend on both the degree of methacrylation and the alginate molecular weight. Due to the chain entanglement present in high-viscosity sodium alginate, lower degrees of modification were required to tune the hydrogel properties. Moreover, in the presence of Ca 2+ , secondary cross-linking was introduced by the coordination of the alginate guluronate moieties with the Ca 2+ ions. The addition of this secondary cross-linking caused fast volume shrinkage and a reinforcement of the mechanical properties. The secondary cross-linking was reversible, and the hydrogels regained their original shape for at least three cycles. Additionally, the dual cross-linked network can be used to induce adhesion between hydrogels and serve as a building block for self-folding actuators.

Crispiness of food products is a key parameter for consumer acceptance. Available methods to evaluate this attribute are subjective and have limitations. They are particularly difficult to implement when granular products are considered. The present study aims to provide a physical characterization of the crispiness of food granular products (gari and grinded corn flakes) based on the compression cycle modeling and the determination of the Py (yield pressure) parameter of the Heckel model. High Py values attributed to the brittle behavior, are indicative of product crispiness. Furthermore, Py parameter showed sensitivity to the plasticizing effect of water. This developed physical method was validated through sensory analysis and acoustic measurements which are both considered as reference methods for crispiness evaluation. The brittle/plastic behavior attributed to crispy/non crispy products respectively was confirmed through image analysis using X-ray microcomputed tomography. The latter made it possible to distinguish the brittle from the plastic behavior through the particle size distribution evolution. This work suggests that the Py value is a relevant indicator for the crispiness evaluation of granular products. This physical characterization is expected to contribute in food engineering as an alternative method for granular products crispiness in a simpler and a more objective way., (© 2023 The Authors. Journal of Texture Studies published by Wiley Periodicals LLC.)

This study exposes the potential usefulness of a new co-processed excipient, composed of alginic acid and microcrystalline cellulose (Cop AA-MCC), for the preparation of immediate drug release tablets by direct compression. Evaluation of the physical and mechanical properties as well as the disintegration behavior of Cop AA-MCC in comparison to commercial co-processed excipients (Cellactose ® , Ludipress ® , Prosolv ® SMCC HD90 and Prosolv ® ODT) and to the physical mixture of the native excipients (MCC and AA), was carried out. The obtained results illustrate the good performance of Cop AA-MCC in terms of powder flowability, tablet tensile strength, compressibility, and disintegration time. Although, this new co-processed excipient showed a slightly high lubricant sensitivity, which was explained by its more plastic than fragmentary deformation behavior, it presented a low lubricant requirement due to the remarkably low ejection force observed during compression. Compression speed and dwell time seemed not to affect significantly the tabletability of Cop AA-MCC. The study exposed evenly the performance of Cop AA-MCC compared to Prosolv ® ODT, in terms of tabletability and dissolution rate of Melatonin. Cop AA-MCC presented comparable hardness, lower dilution potential, higher lubricant sensitivity, lower ejection force, and faster Melatonin's release time than Prosolv ® ODT. In summary, Cop AA-MCC exhibited interesting physical, mechanical, and biopharmaceutical properties, which demonstrate its concurrence to commercially available co-processed excipients. Furthermore, the simplicity of its composition and the scalability of its elaboration makes this multifunctional excipient highly recommended for direct compression.

Maltitol shows interesting properties compared with mannitol or sorbitol, two other polyols, which are widely used as a pharmaceutical excipients for tablet compaction. For this study, the properties of an amorphous polyol, maltitol, were investigated using a tablet press simulator. The aim of this study was to evaluate the behavior of amorphous maltitol compared to SweetPearl® P 200, a pure product, and SweetPearl® P 300 DC, a textured crystalline maltitol excipient for direct compression. The physicochemical and pharmacotechnical properties were compared, revealing a major change in properties after amorphization. The study of the tabletability, mean yield pressure, elastic properties, etc. shows that the compression behavior of amorphous powders has been significantly altered. The results showed specific properties of amorphous maltitol with good tabletability at low compaction pressure. The stability of the amorphous and the evolution of its behavior in compression were then studied, showing a direct link between its recrystallization and the change in its properties. The use of a stabilizing agent, maltotriitol, slowed down the recrystallization, maintaining the specific properties of the amorphous material in compression for a longer period of time.

The implantation of an internal biliary stent (IBS) during liver transplantation has recently been shown to reduce biliary complications. To avoid a potentially morbid ablation procedure, we developed a resorbable and radiopaque internal biliary stent (RIBS). We studied the mechanical and radiological properties of RIBS upon in vivo implantation in rats and we evaluated RIBS implantability in human anatomical specimens. For this purpose, a blend of PLA 50 -PEG-PLA 50 triblock copolymer, used as a polymer matrix, and of X-ray-visible triiodobenzoate-poly(ε-caprolactone) copolymer (PCL-TIB), as a radiopaque additive, was used to design X-ray-visible RIBS. Samples were implanted in the peritoneal cavity of rats. The radiological, chemical, and biomechanical properties were evaluated during degradation. Further histological studies were carried out to evaluate the degradation and compatibility of the RIBS. A human cadaver implantability study was also performed. The in vivo results revealed a decline in the RIBS mechanical properties within 3 months, whereas clear and stable X-ray visualization of the RIBS was possible for up to 6 months. Histological analyses confirmed compatibility and resorption of the RIBS, with a limited inflammatory response. The RIBS could be successfully implanted in human anatomic specimens. The results reported in this study will allow the development of trackable and degradable IBS to reduce biliary complications after liver transplantation. STATEMENT OF SIGNIFICANCE: Biliary reconstruction during liver transplantation is an important source of postoperative morbidity and mortality although it is generally considered as an easy step of a difficult surgery. In this frame, internal biliary stent (IBS) implantation is beneficial to reduce biliary anastomosis complications (leakage, stricture). However, current IBS are made of non-degradable silicone elastomeric materials, which leads to an additional ablation procedure involving potential complications and additional costs. The present study provides in vitro and human postmortem implantation data related to the development and evaluation of a resorbable and radiopaque internal biliary stent (RIBS) that could tackle these drawbacks., Competing Interests: Declarations of Competing Interest None., (Copyright © 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.)

The aim of this study is to investigate the relationship between the structural, molecular, and particulate properties of alginic acid and its functional characteristics in direct compression (tabletability, compressibility, elasticity, deformation mechanism, and disintegration ability). Therefore, accurate characterization of two different batches of alginic acid was executed (X-ray powder diffraction, Fourier-transform infrared spectroscopy, thermogravimetric analysis, scanning electronic microscopy, 1 H nuclear magnetic resonance, size exclusion chromatography - multi angle light scattering, viscosimetry, carboxylic acid titration, powder flowability, true density, laser granulometry). Results showed that molecular weight seems to affect tablet properties and that the alginic acid with the lowest molecular weight provides the hardest tablets with the lowest elastic recovery. Furthermore, these results show the potential interest of exploiting alginic acid as filler excipient in tablet formulation. Finally, disintegration properties of tested materials were found to be close to that of commercial superdisintegrants (Glycolys® and Kollidon Cl®) but not correlated to their swelling force. It can be concluded, for the first time, that the determination of alginic acid molecular weight seems key for applications in direct compression and in particular for obtaining tablets with reproducible strength.

The use of multifunctional excipients is gaining interest as it simplifies formulations by replacing the need of multiple monofunctional excipients. In previous work, coprocessed chitin-calcium carbonate (CC) showed to have good potential as a multifunctional excipient for fast disintegrating tablets produced by direct compression. It allowed for good tablet strength, enhanced powder flowability, and higher true and bulk densities with fast disintegrating properties. The objective of this work is to gain insight on CC tableting properties under different tablet manufacturing conditions (different lubrication levels, compression speeds, and dwell times) and in formulations with drug models: ibuprofen and paracetamol. Results showed that CC exhibited good tabletability, compressibility, and compactibility profiles. CC does not require the addition of lubricant and can be used at high compression speeds and different dwell times. When included in formulations with ibuprofen and paracetamol at different percentages, CC enhanced tablets strength and promoted fast disintegration and drug dissolution. In conclusion, this study shows that CC can be used as a multifunctional excipient (filler-disintegrant-binder) for fast disintegrating tablets produced by direct compression., (Copyright © 2019 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

In the present work heteroionic calcium-magnesium alginate beads have been prepared by ionotropic gelation using different Ca:Mg ratios. This simple and straightforward approach allowed the obtention of CaMg-alginate beads presenting different mechanical performance depending on the Mg:Ca ratio. The dynamic swelling behavior of the beads was investigated. Increase in the quantity of Mg 2+ incorporated in the beads increased the rate of swelling at pH 1.2 and pH 7.2. Finally, the release of ibuprofen was investigated. It was found that increasing the Mg 2+ present in the beads raised the drug release rate., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This study explores the influence of different synthesis methods and drying conditions in the preparation of sodium alginate-derivate xerogels presenting interesting disintegrant functionalities. Xerogels containing alginic acid (AA) or calcium alginate (CaA) and a mixture of both, AA/CaA, were isolated using two different drying methods oven and rotary evaporation. AA showed the best wettability behavior, in contrast to the rigid crosslinked CaA structure which showed a limited rate of water penetration. Interestingly, xerogel containing AA dried in the oven showed an enhanced maximum water uptake. Oven drying seems to favor the isolation of materials presenting good tabletability. Compression parameters of the formulations (tensile strength, elastic energy and porosity) were not affected by their presence (5%) in the design of OroDispersible Mini Tablets. In vitro disintegration results highlighted the water wicking as the key factor leading the disintegration mechanism of these materials. These results show promise of potential properties for the development of super disintegrant excipients., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Mannitol is commonly used as a pharmaceutical excipient for tablets; the most widely used oral dosage form for drug delivery. For tableting, mannitol is provided in two different forms: native crystals and textured particles. In order to optimize its formulation, a good understanding of the mechanical behavior mechanism of mannitol is necessary. Thus, the aim of this study is to evaluate the deformation mechanism of native mannitol crystals presenting different particle sizes. Pharmaco-technical and compression studies were performed using mannitol with different mean diameters (160 µm, 50 µm and 25 µm). Lactose (monohydrate) and microcrystalline cellulose were used as brittle and plastic reference materials, respectively. Tableting tests and mathematical models, HECKEL and WALKER, were used to study the deformation mechanism of mannitol (β). Mean Yield Pressure (Py) and WALKER coefficient (W) values showed that the studied crystalline mannitol presents a deformation mechanism close to brittle material. A particle-size analyzer was used at different pulverization pressures to show the high sensibility of the mannitol particles to fragmentation when exposed to high pressures, especially for particles presenting 160 µm size. Scanning Electron Microscopy (SEM) was used to show the fragmentation after high-pressure measurements., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Owing to the increasing interest in multifunctional excipients for tableting, coprocessing of individual excipients is regularly used to produce excipients of improved multifunctionality superior to individual excipients or their physical mix. The use of chitin as an excipient in tablet formulation is limited because of certain drawbacks such as poor flowability and low true density. The objective of this work is to improve these properties through coprocessing of chitin with calcium carbonate (CaCO 3 ) by precipitating CaCO 3 on chitin particles using different methods. In addition, optimization of the coprocessed chitin was carried out to improve the excipient's properties. Physicochemical (CaCO 3 content, true density, X-ray diffraction, infrared spectroscopy, and scanning electron microscopy) and functional testing (swelling force, flowability, tensile strength, deformation mechanism, and disintegration time) were used to characterize the coprocessed product. Results showed that the calcite CaCO 3 polymorph is precipitated on the chitin surface and that it interacts with chitin at carbonyl- and amide-group level. In addition, the coprocessed excipient has an improved true density and powder flowability, with CaCO 3 forming single layer on the chitin particles surface. Tableting studies showed that the coprocessed powder exhibited an intermediate deformation behavior between CaCO 3 (most brittle) and chitin (most plastic). Tablets showed acceptable tensile strength and rapid disintegration (2-4 s). These results show the potential use of coprocessed chitin-CaCO 3 as a multifunctional excipient for fast disintegration of tablets produced by direct compression., (Copyright © 2018 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

This study applied the concept of Quality by Design (QbD) to tablet dissolution. Its goal was to propose a quality control strategy to model dissolution testing of solid oral dose products according to International Conference on Harmonization guidelines. The methodology involved the following three steps: (1) a risk analysis to identify the material- and process-related parameters impacting the critical quality attributes of dissolution testing, (2) an experimental design to evaluate the influence of design factors (attributes and parameters selected by risk analysis) on dissolution testing, and (3) an investigation of the relationship between design factors and dissolution profiles. Results show that (a) in the case studied, the two parameters impacting dissolution kinetics are active pharmaceutical ingredient particle size distributions and tablet hardness and (b) these two parameters could be monitored with PAT tools to predict dissolution profiles. Moreover, based on the results obtained, modeling dissolution is possible. The practicality and effectiveness of the QbD approach were demonstrated through this industrial case study. Implementing such an approach systematically in industrial pharmaceutical production would reduce the need for tablet dissolution testing.

Objective: This work evaluates the functionalities of different superdisintegrants (SD) for manufacturing orodispersible mini tablets (ODMT) by direct compression., Methods: Twenty-three formulations varying in SD type, concentration, and lubricant were used to manufacture ODMT. The ODMT were then characterized for the following properties: friability, porosity, tensile strength, in vivo and in vitro disintegration time (DT)., Results: The results show that the presence, type, and concentration of SD did not influence friability, porosity, or tablet tensile strength. With regards to in vivo DT, only cross-linked poly (vinyl pyrrolidone) improved DT in all the tested formulations. Results also showed that when using microcrystalline cellulose (MCC) above 20% in the formulation, DT is longer. Cross-linked carboxymethyl cellulose accelerates DT when the MCC content is less than 20%. As for cross-linked carboxymethyl starch and calcium alginate showed no improvement on DT. Results for in vitro DT were all shorter than in vivo results and there was no correlation with the in vivo evaluation., Conclusions: This study shows that there is a need to develop better in vitro testing that precisely simulates in vivo conditions and that are adapted to ODMT. This standardization of the test methods for ODMTs must be accompanied by an improvement in the comprehension of SD mechanisms.

Disintegrants are used as excipients to ensure rapid disintegration of pharmaceutical tablets and further ensure proper dissolution of the active pharmaceutical ingredient. This study investigates disintegration mechanisms of chitin and common disintegrants. Swelling assessment (swelling force and swelling ratio) in different media, and compaction behavior (pure or mixed with other excipients) tabletability, deformation (Heckel modeling), and compact disintegration times were investigated on the tested disintegrants (alginic acid calcium salt, crospovidone, sodium starch glycolate, croscarmellose sodium, and chitin). Results show that the physicochemical properties of the disintegration medium such as pH and ionic strength, as well as other formulation ingredients, affect the disintegrant functionalities. Heckel analysis using the mean yield pressure "Py" shows that alginic acid calcium salt is the most brittle among the studied disintegrants, while crospovidone has the most plastic deformation mechanism, followed by chitin. Chitin showed good tabletability and disintegration properties that were not influenced by the physicochemical formulation environment. Chitin is largely available and easily modifiable and thus a promising material that could be used as a multifunctional excipient in tablet formulation., (Copyright © 2017 American Pharmacists Association®. Published by Elsevier Inc. All rights reserved.)

Background: Arterial Remodeling Technologies bioresorbable scaffold (ART-BRS), composed of l- and d-lactyl units without drug, has shown its safety in a porcine coronary model at 6 months. However, long-term performance remains unknown. The aim of this study was to evaluate the ART-BRS compared to a bare metal stent (BMS) in a healthy porcine coronary model for up to 3 years., Methods and Results: Eighty-two ART-BRS and 66 BMS were implanted in 64 Yucatan swine, and animals were euthanatized at intervals of 1, 3, 6, 9, 12, 18, 24, and 36 months to determine the vascular response using quantitative coronary angiography, optical coherence tomography, light and scanning electron microscopy, and molecular weight analysis. Lumen enlargement was observed in ART-BRS as early as 3 months, which progressively increased up to 18 months, whereas BMS showed no significant difference over time. Percentage area stenosis by optical coherence tomography was greater in ART-BRS than in BMS at 1 and 3 months, but this relationship reversed beyond 3 months. Inflammation peaked at 6 months and thereafter continued to decrease up to 36 months. Complete re-endothelialization was observed at 1 month following implantation in both ART-BRS and BMS. Scaffold dismantling started at 3 months, which allowed early vessel enlargement, and bioresorption was complete by 24 months., Conclusions: ART-BRS has the unique quality of early programmed dismantling accompanied by vessel lumen enlargement with mild to moderate inflammation. The main distinguishing feature of the ART-BRS from other scaffolds made from poly-l-lactic acid may result in early and long-term vascular restoration., (© 2017 The Authors and Arterial Remodeling Technologies. Published on behalf of the American Heart Association, Inc., by Wiley.)

Textured mannitol powder is widely used as a pharmaceutical excipient for tablet compaction. In order to choose the right tableting parameters, it is necessary to understand its mechanical behavior during deformation under industrial tableting conditions. The aim of this study was to evaluate the mechanical behavior during deformation of a textured mannitol using a rotary tablet press simulator. Mean yield pressure (Py) obtained by Heckel modeling, Walker coefficients (W) and Stress Rate Sensitivity (SRS) were compared to reference excipients, known for either their plastic (microcrystalline cellulose) or fragmentary (lactose and dibasic calcium phosphate) deformation behavior. Py, W and SRS values showed that the studied textured mannitol has a fragmentary deformation mechanism. Furthermore, this mechanical behavior was not sensitive to lubrication, which is characteristic of fragmentary excipients., (Copyright © 2015 Elsevier B.V. All rights reserved.)

The aim of this work is to improve the understanding of the physicochemical mechanisms involved in the functionality of cross-linked carboxymethyl sodium starch (CCSS) as a tablet super disintegrant (SD). The behavior and properties of this SD (medium uptake, disintegration times, particle size, and rheology) was investigated in a wetting medium of different physicochemical properties. In particular, the relative permittivity (dielectric constant) of these media was intentionally modified for evaluating its effect on CCSS properties. Results showed different swelling behaviors of CCSS particles according to the relative permittivity of the tested media and allow to propose two underlying mechanisms that explain CCSS functionality. Both the intra-particular swelling and the inter-particular repulsion are affected by the relative permittivity of the media. Finally, disintegration test performed on tablets specially formulated with mannitol (used commonly as an excipient and known to modify relative permittivity) confirmed that the functionality of CCSS and therefore the disintegration of the tablet can be altered according to the mannitol content.

The aim of this work was to investigate an alternative processing technology for a new polymeric solubilizer used mainly in hot melt extrusion. Poorly soluble nifedipine was co-processed through spray-drying with poly(vinyl caprolactam-co-vinyl acetate-co-ethylene glycol) (PVCVAEG) in different ratios. The resulting spray-dried powders were formulated and compacted into tablets forms. Spray drying produced reduced smooth spherical particles with PVCVAEG and more rough surfaces without PVCVAEG. Crystallinity of the co-processed nifedipine with the polymeric solubilizer was reduced. Plasticization of the polymeric solubilizer was observed with increasing drug content. Diffraction patterns in the small angle region as well as transmission electron microscopy showed results supporting phase separation throughout the spray dried particles of high drug content. Compaction with PVCVAEG improved cohesiveness of spray-dried compacts. Heckel modeling showed that deformation of PVCVAEG containing powders was more plastic compared than brittle nifedipine powders. Dissolution kinetics of all spray-dried samples was improved compared to original nifedipine crystals. Co-processed nifedipine with PVCVAEG did not show improved dissolution rate when compared to spray drying nifedipine alone. All though PVCVAEG is more commonly co-processed with drugs by hot melt extrusion to produce solid dispersions, the results show that it also can be processed by spray drying to produce solid dispersions. PVCVAEG improved compactibility of formulated spray dried powders., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Near infrared chemical imaging (NIRCI) is a common analytical non-destructive technique for the analysis of pharmaceutical tablets. This powerful process analytical technology provides opportunity to chemically understand the sample, and also to determine spatial distribution and size of ingredients in a tablet. NIRCI has been used to link disintegrant, excipients and active pharmaceutical ingredient (API) to tablet dissolution, as disintegrants play an important role in tablet disintegration, resulting in API dissolution. This article describes a specific methodology to predict API dissolution based on disintegrant chemical information obtained with NIRCI. First, several tablet batches with different disintegrant characteristics were produced. Then, NIRCI was successfully used to provide chemical images of pharmaceutical tablets. A PLS regression model successfully predicted dissolution profiles. These results show that NIRCI is a robust and versatile technique for measuring disintegrant properties in tablet formulations and predicting their effects on dissolution profiles. Thus, NIRCI could routinely complement and eventually replace dissolution testing by monitoring a critical material attribute: disintegrant content., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Poly(l-lactic acid) (PLLA) membranes containing pharmaceutically active ionic liquids (API-ILs) have been prepared by using a simple film casting from solvent evaporation method. Several sets of membranes were prepared from two different ionic liquids namely 1-methyl-3-butyl-imidazolium ibuprofenate (C 4 MImIbu) and lidocainium ibuprofenate (LidIbu) with different API-IL contents. Scanning Electron Microscopy (SEM), Differential Scanning Calorimetry (DSC), Wide-Angle and Small-Angle X-ray Scattering (WAXS and SAXS) revealed the strong influence of both the IL nature and content on the morphology and the crystallinity of the resulting PLLA. At 20 weight%, LidIbu was shown to act as a plasticizer for PLLA and homogeneous membranes were obtained. In contrast, at the same IL content, phase separation occurred using C 4 MImIbu, resulting in the formation of porous PLLA. An increase of LidIbu content to 50 weight% results also in phase separation. 1 H and 1 H- 13 C CP-MAS NMR measurements evidenced the influence of different morphologies and crystallinities on IL mobility. C 4 MImIbu was found to be highly mobile whereas the mobility of LidIbu was content dependent. At low percent, low mobility was observed while at higher content, two populations with respectively high and low mobility were observed. These PLLA-IL membranes were further tested as drug delivery systems. In accordance with the morphology and mobility obtained, we demonstrated that release kinetics from PLLA membranes can be tuned by the nature and the content of API-ILs. Sustainable release kinetics were obtained with API-IL acting as a plasticizer while the fastest release was obtained with API-IL acting as a porogenic agent.

Background: We aimed to evaluate a new drug-free fully bioresorbable lactic acid-based scaffold designed to allow early dismantling synchronized with artery wall healing in comparison with a bare metal stent (BMS)., Methods and Results: Twenty-three BMS (3.0×12 mm) and 36 lactic acid-based bioresorbable scaffolds (BRS, 3.0×11 mm) were implanted in porcine coronary arteries. QCA and optical coherence tomographic analyses were performed immediately after implantation and repeated after 1, 3, and 6 months. Microcomputed tomography was used to detect scaffold dismantling. Polymer degradation was evaluated throughout the study. The primary end-point was late lumen loss, and the secondary end-points were scaffold/stent diameter and acute recoil. Acute recoil was low and comparable between the BRS and the BMS groups (4.6±6.7 versus 4.6±5.1%; P=0.98). BRS outer diameter increased significantly from 1 to 6 months indicating late positive scaffold remodeling (P<0.0001), whereas BMS diameter remained constant (P=0.159). Late lumen loss decreased significantly from 1 to 6 months in the BRS group (P=0.003) without significant difference between BRS and BMS groups at 6 months (P=0.68). Microcomputed tomography identified BRS dismantling starting at 3 months, and weight-average molar masses of scaffold parts were 20% and 14% of their initial values at 3 and 6 months., Conclusions: BRS and BMS have similar 6-month outcomes in porcine coronary arteries. Interestingly, BRS dismantling was detected from 3 months and resulted in late lumen enlargement by increased scaffold diameter at 6 months.

Aims: To assess the impact of the composition in L- and D- of lactic acid stereo copolymers without drug elution on the in situ behaviour of prototype stents in terms of biomechanics and biocompatibility., Methods and Results: PLA50, 75, and 92 stereo-copolymer stents (L/D lactic acid ratio from 1 to 11.5) were processed using the injection moulding facilities of Arterial Remodeling Technologies (Noisy le Roi, France). The resulting 3 mm outer diameter tubes having a diameter at the desired nominal size were laser-cut and crimped on regular angioplasty balloons and chemically sterilised prior to implantation in iliac rabbit arteries. Acute recoil was higher in PLA50 and PLA75 stent-treated arteries than in those with PLA92 stents (17.4 ± 11.4 vs. 13.5 ± 7.6 vs. 4.1 ± 3.8 %, respectively, p=0.001). At one month, in-stent area was higher in PLA92 than in PLA50 and PLA75 stented arteries (5.9 ± 0.6 vs. 1.6 ± 1.6 vs. 2.6 ± 3.2 mm², respectively, p<0.001). Re-endothelialisation was complete, and inflammation was mild around the struts, similar among the three stents. Late lumen loss and neointimal area were low and similar in PLA92 stent-treated arteries one and six months after angioplasty (0.2 ± 0.2 vs. 0.3 ± 0.2 mm, p=0.60; 0.5 ± 0.5 vs. 0.5 ± 0.8 mm², p=0.72, respectively). At six months, inflammation decreased compared to one-month follow-up (1.4 ± 0.5 vs. 0.6 ± 0.5, p=0.006)., Conclusions: A stereo-copolymer composition strongly influences biomechanical properties of PLA bioresorbable stents in agreement with what has been known for a long time from other applications, but not biocompatibility. PLA92 stents appeared as presenting acceptable acute deployment and 6-month favourable outcome in the rabbit model despite the absence of drugs.

This work describes a simple method to immobilize heparin by covalent bonding to the surface of poly(lactic acid) film with the aim of showing improved hemocompatibility. Carboxyl groups present in heparin molecules were activated by reaction with N-hydroxy-succinimide and allowed to react with free amino groups created at the surface of poly(DL-lactic acid) films by controlled aminolysis. Contact angle measurements and XPS analysis confirmed the binding. Quantification was determined by radioactivity using heparin labeled with tritium. The surface exhibited anti factor Xa activity, thus confirming the presence of bounded heparin that kept some biological activity. Finally platelets adhesion showed less platelet adhesion on heparin modified films as well as preserved morphology., (Copyright © 2011 Wiley Periodicals, Inc.)

The release behaviour of clozapine matrix pellets was studied in order to investigate if it is possible to explain it applying the concepts of percolation theory, previously used in the understanding of the release process of inert and hydrophilic matrix tablets. Thirteen batches of pellets with different proportions of clozapine/microcrystalline cellulose (MCC)/hydroxypropylmethyl cellulose (HPMC) and different clozapine particle size fractions were prepared by extrusion-spheronisation and the release profiles were studied. It has been observed that the distance to the excipient (HPMC) percolation threshold is important to control the release rate. Furthermore, the drug percolation threshold has a big influence in these systems. Batches very close to the drug percolation threshold, show a clear effect of the drug particle size in the release rate. However, this effect is much less evident when there is a bigger distance to the drug percolation threshold, so the release behaviour of clozapine matrix pellets is possible to be explained based on the percolation theory., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Stent implantation following angioplasty is the standard treatment of coronary artery disease necessitating interventional procedures. The use of stents as a platform for local drug delivery is a popular strategy to achieve local pharmacological treatment to the diseased artery. Drug eluting stents (DES) are now largely preferred to bare metal stents when stent implantation is necessary. Lately, there have been several reports questioning the long-term safety of DES. An alternative to these drug eluting metal stents are bioresorbable polymeric stents (BPS) because of the many advantages of bioresorbable material. However, the fundamental differences in polymeric and metallic materials make the development of such an alternative a significant challenge. This review discusses the different advantages of BPS and the many constrains and requirements of such devices. An up to date commented review of published data concerning BPS is presented. Considerations are given on using BPS as local drug delivery systems as well as on evaluating BPS performances., (Copyright 2007 Wiley-Liss, Inc.)